1. Field of the Invention
The present invention relates to a fuel tank for use in a vehicle.
2. Description of the Related Art
A vehicle driven by an internal combustion engine is normally equipped with a fuel tank. In such a vehicle, when the amount of fuel in the fuel tank is to be replenished, a cap attached to a fuel inlet of the fuel tank is removed, a fuel pump nozzle is inserted into the fuel inlet, and fuel is fed into the fuel tank from the fuel pump nozzle. However, when the amount of fuel in the fuel tank is small, the space above the liquid surface of the fuel in the fuel tank is filled with a large amount of fuel vapor under pressure. Consequently, when the cap attached to the fuel inlet is removed, the fuel vapor flows out from the fuel inlet into the outside air, causing air pollution. In addition, when the fuel is fed into the fuel tank from the fuel pump nozzle, the fuel spouted from the fuel pump nozzle comes into violent contact with and agitates the fuel in the fuel tank, causing a large amount of fuel vapor to be generated in the fuel tank. As a result, the fuel vapor gradually flows into the outside air as the liquid surface of fuel in the fuel tank is raised, also causing air pollution.
To prevent this air pollution, a fuel tank is known in which a normally closed closure valve, which is opened when the fuel pump nozzle is inserted into the fuel inlet, is pivotally arranged in the fuel inlet pipe, and a normally closed control valve is also arranged in the fuel inlet pipe to control the flow of fuel vapor flowing from the fuel tank towards a fuel vapor purifying device. When the closure valve is opened, the control valve is also opened, and thus the fuel vapor in the fuel tank is fed into a fuel vapor purifying device (Japanese Unexamined Utility Model Publication No. 61-90624).
In addition, to prevent such air pollution, another fuel tank has been proposed in which a normally closed closure valve, which is opened when the fuel pump nozzle is inserted into the fuel inlet, is pivotally arranged in the fuel inlet pipe, and a normally closed control valve is also pivotally arranged in the fuel inlet pipe to control the flow of fuel vapor flowing from the fuel tank towards a fuel vapor purifying device. When the closure valve is opened, the control valve is also opened, and thus the fuel vapor in the fuel tank is fed into the fuel vapor purifying device (Japanese Utility Model Application No. 60-169614).
However, the cross-sectional area of the fuel inlet pipe is small, and thus, when the control valve is arranged in the fuel inlet pipe in addition to the closure valve, a problem occurs in that the mounting of the control valve is difficult. In addition, it is necessary to arrange the control valve so that it does not obstruct the fuel pump nozzle when inserted into the fuel inlet pipe, and thus another problem occurs in that it is impossible to give the control valve a large enough fuel vapor flow area.